High temperature seal

ABSTRACT

A seal comprising a high temperature silicone adhesive sealant layer; a first non-ceramic layer mounted to the silicone adhesive sealant layer; a first expanded metal layer mounted to the first non-ceramic layer; a first silicone cloth layer mounted to the first expanded metal layer; a metal reinforcement layer mounted to the first silicone cloth layer to provide structural integrity without the use of ceramic materials; a second expanded metal layer mounted to the metal reinforcement layer; a second non-ceramic layer mounted to the second expanded metal layer; a turbine mesh layer mounted to the second non-ceramic layer; a second silicone cloth layer mounted to the turbine mesh layer; a sealing castable applied over the second silicone cloth layer to provide a covering; and, a high temperature bonding adhesive disposed between each layer following the first non-ceramic layer to bind the layers together.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.12/148,009 filed Apr. 16, 2008 which in turn claims priority from U.S.Provisional Application Ser. No. 60/923,712, filed Apr. 16, 2007.

FIELD OF THE INVENTION

This invention relates to a seal construction and method for hightemperature sealing and more specifically to a system and method forsealing cracks and filling dead air spaces in the high temperatureenvironment of a boiler assembly.

BACKGROUND OF THE INVENTION

During the operation of a boiler, many of the steam and water tubesexpand and contract in response to the thermal effects caused byexpansion and contraction. Therefore, the seals, such as those betweendead air spaces and the boiler, have been difficult to maintain. Sincesteel is the principal material used for the construction of boilers,its inelasticity prevents a durable seal from being maintained becausein stead of flexing to expand and contract, the material instead isprone to fracture. When cracks or other leaks exist in the boiler,flue-gas that may carry fly-ash, can enter through these leaks andsettle in the dead air space or even travel into the boilerhouse.Leakages have an adverse effect on the efficiency of the operation ofthe boiler and it is therefore desirable to reduce if not eliminate theleakages which occur due to thermal expansion and contraction. Leakagescause excess air to be introduced within the boiler and can increaseslagging, cause loss on ignition, increase the need for superheat orreheat attempt or spraying, and increase the corrosion within theboiler. Cracks and leaks have been responsible for upper-furnace slagproblems due to excessive air in leakage through cracks and leaks in thepenthouse floor. Repairs are frequently needed of the penthouse toremedy these cracks and leaks.

Historically, cracks and leaks have been repaired through welding thesteel to contain the leak or crack. However, the weld itself is alsosubject to thermal expansion and therefore, does not maintain itsintegrity and when the boiler heats and cools, eventually more cracksand leaks develop.

One such product that has been useful in repairing these leaks is aproduct distributed under the trademark ISOMEMBRANE®. This product isavailable from High Temperature Technologies, Inc., a North Carolinacorporation, and has been used in sealing cracks and leaks withoutlosing its seal integrity due to thermal expansion and contraction.ISOMEMBRANE® is a flexible high temperature resistant seal. ISOMEMBRANE®has a sandwich construction consisting of layers of high density fibers(ISOBLANKET-E), high temperature adhesive (ISOBOND-E) and a sealingcastable (ISOCOAT-E) to finish the surface. It is capable of sealingleaks and cracks in boilers which have an environment that does notallow welds or other sealing means to keep their integrity due tothermal expansion and contraction caused by the heat associated with aboiler.

By way of example, ISOMEMBRANE® has been credited with reducing slaggingand improving the operational condition of a boiler in Alabama whichresulted in saving the boiler operations nearly $1.7 million dollarsannually. However, ISOMEMBRANE® uses a refractory ceramic fibre (RCF)which has been known to cause irritation of the skin, eyes and upperrespiratory tract, and can be inhaled and deposited in the lungs if theRCF is fine enough. It has also been alleged that RCFs can produce lungfibrosis, lung cancer, and also mesothelioma following long-terminhalation.

Therefore, it is desirable to have a boiler sealer which has theadvantages of ISOMEMBRANE without having RCFs in its construction orcomposition.

SUMMARY OF THE INVENTION

This object of the present invention is accomplished by providing a sealfor use in high temperature environments of a boiler assembly to remedycracks and air leaks, the seal comprising a high temperature RTVsilicone adhesive sealant layer; a first non-ceramic layer mounted tothe RTV silicone adhesive sealant layer; a first expanded metal layermounted to the first non-ceramic layer; a first silicone cloth layermounted to the first expanded metal layer; a metal reinforcement layermounted to the first silicone cloth layer to provide structuralintegrity without the use of ceramic materials; a second expanded metallayer mounted to the metal reinforcement layer; a second non-ceramiclayer mounted to the second expanded metal layer; a turbine mesh layermounted to the second non-ceramic layer; a second silicone cloth layermounted to the turbine mesh layer; a sealing castable applied over thesecond silicone cloth layer to provide a covering; and, a hightemperature bonding adhesive disposed between each layer following thefirst non-ceramic layer to bind the layers together.

In a further advantageous embodiment, the first non-ceramic layerconsists of ISOBLANKET-E material, and the second non-ceramic layerconsists of ISOBLANKET-E material.

In a further advantageous embodiment, the high temperature bondingadhesive sealant applied between each layer consists of ISOBOND-E.

In a further advantageous embodiment, the sealing castable consists ofISOCOAT.

In a further advantageous embodiment, the invention provided for a sealfor use in high temperature environments of a boiler assembly to remedycracks and air leaks for expansion joints, the seal comprising a latticeof support studs and support bars having a plurality of support postsextending outwardly there from, wherein the lattice is secured to adesired area of the boiler assembly; a high temperature RTV siliconeadhesive sealant layer applied to the lattice; a first non-ceramic layermounted to the support posts over the RTV sealant layer; a firstexpanded metal layer mounted to the support posts and applied to thefirst non-ceramic layer; one of a first silicone cloth layer and a firstfoil layer mounted to the support posts and applied to the firstexpanded metal layer; a second non-ceramic layer mounted to the supportposts and applied to the first silicone cloth layer or the first foillayer; a turbine mesh layer mounted to the support posts and applied tothe second non-ceramic layer; one of a second silicone cloth layer and asecond foil layer mounted to the support posts and applied to theturbine mesh layer; a second expanded metal layer mounted to the supportposts and applied to the second silicone cloth layer or the second foillayer; a high temperature bonding adhesive disposed between each layerto bind the layers together; and, securing members operativelyassociated with the support posts to secure the first non-ceramic layer,the first expanded metal layer, the first silicone cloth or foil layer,the second non-ceramic layer, the turbine mesh layer, the secondsilicone cloth or foil layer and the second expanded metal layer againstthe lattice.

In a further advantageous embodiment, the first non-ceramic layerconsists of ISOBLANKET-E material, and the second non-ceramic layerconsists of ISOBLANKET-E material.

In a further advantageous embodiment, the high temperature bondingadhesive sealant applied between each layer consists of ISOBOND-E.

In a further advantageous embodiment, the invention provides for a sealfor use in high temperature environments of a boiler assembly to remedycracks and air leaks for dead air space, the seal comprising a latticeof support studs and support bars having a plurality of support postsextending outwardly there from, wherein the lattice is secured to adesired area of the boiler assembly; a high temperature adhesive layerapplied to the lattice; a first non-ceramic layer carried by the supportposts adjacent the adhesive layer; a turbine mesh layer carried by thesupport posts adjacent the first non-ceramic layer; an expanded metallayer carried by the support posts following the turbine mesh layer; asealing castable applied over the expanded metal layer to provide acovering; and, securing members operatively associated with the supportposts to secure the first non-ceramic layer, the turbine mesh layer, theexpanded metal layer and the sealing castable against the lattice.

In a further advantageous embodiment, the high temperature adhesivelayer consists of ISOBOND-E.

In a further advantageous embodiment, the first non-ceramic layerconsists of ISOBLANKET-E material.

In a further advantageous embodiment, a second non-ceramic layer isdisposed between the turbine mesh layer and the expanded metal layercarried by the support posts.

In a further advantageous embodiment, the sealing castable consists ofISOCOAT.

In a further advantageous embodiment, the invention provides for a sealfor use in high temperature environments of a boiler assembly to remedycracks and air leaks, the seal comprising a lattice of support studs andsupport bars having a plurality of support posts extending outwardlythere from, wherein the lattice is secured to a desired area of theboiler assembly; a high temperature RTV silicone adhesive sealant layerapplied to the lattice; a first expanded metal layer carried by thesupport posts adjacent the RTV sealant layer; a first silicone clothlayer carried by the support posts adjacent the first expanded metallayer; a non-ceramic layer carried by the support posts adjacent thefirst silicone layer; a turbine mesh layer carried by the support postsadjacent the first non-ceramic layer; a second silicone cloth layercarried by the support posts adjacent the turbine mesh layer; a secondexpanded metal layer carried by the support posts adjacent the secondsilicone cloth layer; and, securing members operatively associated withthe support posts to secure the first expanded metal layer, the firstsilicone cloth, the non-ceramic layer, the turbine mesh layer, thesecond silicone cloth and the second expanded metal layer against thelattice.

In a further advantageous embodiment, the non-ceramic layer consists ofISOBLANKET-E material.

In a further advantageous embodiment, a high temperature bondingadhesive is disposed between each layer to bind the layers together.

In a further advantageous embodiment, the high temperature adhesivelayer consists of ISOBOND-E.

In a further advantageous embodiment, the invention provides for amethod for installing a seal for use in high temperature environments ofa boiler assembly to remedy cracks and air leaks for expansion joints,the method comprising the steps of providing a lattice of support studsand support bars having a plurality of support posts extending outwardlythere from; securing the lattice to a desired area of the boilerassembly; applying a high temperature RTV silicone adhesive sealantlayer to the lattice; applying a first non-ceramic layer onto thesupport posts; applying a first expanded metal layer onto the supportposts adjacent the first non-ceramic layer; applying one of a firstsilicone cloth layer and a first foil layer onto the support postsadjacent the first expanded metal layer; applying a second non-ceramiclayer onto the support posts adjacent the first silicone cloth layer orthe first foil layer; applying a turbine mesh layer onto the supportposts adjacent the second non-ceramic layer; applying one of a secondsilicone cloth layer and a second foil layer onto the support postsadjacent the turbine mesh layer; applying a second expanded metal layeronto the support posts adjacent the second silicone cloth layer or thesecond foil layer; applying a high temperature bonding adhesive betweeneach layer to bind the layers together; and, securing the firstnon-ceramic layer, the first expanded metal layer, the first siliconecloth or foil layer, the second non-ceramic layer, the turbine meshlayer, the second silicone cloth or foil layer and the second expandedmetal layer against the lattice.

In a further advantageous embodiment, the invention provides for amethod for installing a seal for use in high temperature environments ofa boiler assembly to remedy cracks and air leaks for dead air space, theseal comprising providing a lattice of support studs and support barshaving a plurality of support posts extending outwardly there from;securing the lattice to a desired area of the boiler assembly; applyinga high temperature adhesive layer to coat all exposed surfaces of thelattice; applying a first non-ceramic layer onto the support posts;applying a turbine mesh layer onto the support posts adjacent the firstnon-ceramic layer; applying an expanded metal layer onto the supportposts following the turbine mesh layer; applying a sealing castable overthe expanded metal layer to provide a covering; and, securing the firstnon-ceramic layer, the turbine mesh layer, the expanded metal layer andthe sealing castable against the lattice.

In a further advantageous embodiment, the method includes applying asecond non-ceramic layer between the turbine mesh layer and the expandedmetal layer onto the support posts.

DESCRIPTION OF THE DRAWINGS

The construction designed to carry out the invention will hereinafter bedescribed, together with other features thereof. The invention will bemore readily understood from a reading of the following specificationand by reference to the accompanying drawings forming a part thereof,wherein an example of the invention is shown and wherein:

FIG. 1 is a diagram of the environment where the invention can beinstalled;

FIG. 2 is a side cross-section view of the penthouse of a boiler;

FIG. 2A is top plan view of the penthouse of a boiler;

FIG. 2B is an alternative side cross-section view of the penthouse of aboiler;

FIG. 3 is a perspective cut-away view of the seal layers according tothe present invention;

FIG. 4 is a perspective view of some layers of the invention;

FIG. 5 is a flowchart illustrating the invention;

FIG. 5A is a flowchart illustrating the invention;

FIG. 6 is a flowchart illustrating the invention;

FIG. 7 is a perspective view of the invention; and,

FIG. 8 is a perspective view of the invention.

DESCRIPTION OF THE INVENTION

Referring to FIG. 1, the invention comprises a system and method forsealing leaks and cracks, particularly those which develop in a boiler.A boiler can have a penthouse, shown generally as 10, having a floor 12and pipes 14 extending through the floor of the penthouse. The junction16 between the penthouse floor and the pipes is an area that, due tothermal effects, experiences multi-plane movement and develops cracksduring the operation of the boiler. Other areas of a boiler that canbenefit from the present invention include a lower vestibule 18, acombustion air duct 20, a casing 22, a drum vestibule 24, a convectionpass casing 26, a nose arch vestibule 28, an ash hopper 30, a flue gasducting 32, an air heater 34, a precipitator inlet 36, a precipitatorcasing 38, a precipitator penthouse 40, a precipitator casing 42, and aprecipitator outlet 44. Any area which develops air leaks or cracks dueto thermal expansion or any ductwork expansion joint in a boiler canbenefit from this invention.

Referring to FIG. 2, a side cross-section view is shown of an embodimentof the invention installed on a penthouse of a boiler. Penthouse floor12 is shown carrying pipes 14. Cracks and air leaks can develop in area16. To remedy these air leaks and cracks, the layers of the inventionare shown as 50 covering area 16. In FIG. 2A, a top view of penthousefloor 12 with pipes 14 extending through the floor is shown. A sealingcasting 46 such as ISOCOAT-E is shown covering expanded metal 48providing the seal on the penthouse penetrations. FIG. 2B is a crosssection along lines B of FIG. 2. In FIG. 2B, pipes 14 are shownextending through the penthouse floor 12. The layers of the inventionshown as 50 are illustrated covering the area 16 which may containcracks or air leaks.

Referring now to FIG. 3, the several layers of the invention are shownwhich are installed on boiler assemblies to remedy cracks and air leaks.In one embodiment of the invention, the several layers include a hightemperature RTV Silicone Adhesive sealant 52, preferably of the typecontaining among other things silica, amorphous (fumed) andmethyltriactoxysilane, which is commonly available in the marketplace. Afirst non-ceramic layer 54 of ISOBLANKET-E is then applied which is usedfor high temperature application and water soluble for safety concerns.These products are non-respirable, offer zero shot content, and offerexceptional tensile strengths. Silica blankets are highly resilient, andoffer resistance to degradation due to vibrations. Further, suchblankets can actually increase in strength under heightenedtemperatures. It is advantageous to use such non-ceramic blankets asceramic layers contain health risks that are not present with thesenon-ceramic blankets. Next, a first expanded metal layer 56 is providedadjacent to the first non-ceramic layer 54. In a further embodiment,first expanded metal layer 56 includes a first silicone cloth (Silcloth) 58. A second expanded metal layer 60 as well as a secondnon-ceramic layer 62 of ISOBLANKET-E can be included thereafter. Aturbine mesh layer 64 can be included as well as a second silicone clothlayer 66. The layers can be sealed with a sealing castable 68 forcovering. Further, between each layer can be a high temperature sealantsuch as ISOBOND-E® which is available from High TemperatureTechnologies. Since non-ceramic insulation, while providing healthadvantages, may not have the structural integrity that is realized fromceramic insulations, in the preferred embodiment, a metal reinforcementlayer 59 is placed between the first sil cloth layer 58 and secondexpanded metal layer 60 to provide the structural integrity realizedfrom ceramic insulators without having the disadvantages of ceramicmaterials.

Referring to FIG. 4, in some installation, studs 70 are welded orotherwise attached to the boiler for supporting the layers of thepresent invention. The invention is shown in a vertical installationconfiguration, for example, against a wall. A support stud 70 havingposts 71 is welded or otherwise attached to the boiler assembly. Furthersupport bars such as 74 a and 74 b, which also carry posts 71, can beadded to provide further support for the layers of this invention. Thelayers of the present invention can then be bolted to the support studs70 on posts 71 using washers 72 or other fastening member. The layerscan be attached to one or both sides of the studs depending on theapplication as illustrated.

Referring now to FIG. 5, an installation process is described forexpansion joint application, which utilized a modified layer structure.In one embodiment, support studs 70 and support bars 74 are firstthreaded together at step 99 and installed in the appropriate manneragainst or around the relevant area of the boiler system at step 100. AnRTV sealant layer is place at step 102. A first non-ceramic layer ofISOBLANKET-E is then installed at step 103 over the RTV sealant. A firstexpanded metal layer is installed over the first non-ceramic layer atstep 104. The first Sil cloth layer is then installed over the firstexpanded metal layer at step 106. A second non-ceramic layer isinstalled over the sil cloth at step 108. ISOBOND-E® is installed atbetween layers, as designated at step 110. A turbine mesh 64 is over thesecond non-ceramic layer at step 112 and ISOBOND-E® can again beinstalled between these layers at 113. The second Sil cloth can next beadded at step 114. A second expanded metal layers is finally added atstep 116 and the layers can be attached to the studs at step 118. Again,ISOBOND-E is installed between these an all other layers. Generally,these steps are used to remedy cracks and stop leakages. However, thisinvention can also be used to fill dead air spaces which are undesirablein a boiler and its environment.

Referring to FIG. 5A, an alternative arrangement of the invention mayalso be used to deal with expansion joint issues. Instead of using Silcloth at steps 106 and 114 of FIG. 5, foil is used. After the firstexpanded metal layer is installed at 104, a first foil layer isinstalled at 105. Therefore, a first foil layer is substituted for afirst Sil cloth layer. Further, after a second ISOBOND layer isinstalled at 113, a second foil layer 115 is installed. Again, Sil clothis substituted with foil layer and ISOBOND is applied between all otherlayers.

Referring to FIG. 6, this invention is further described for use infilling dead air space in a boiler environment. When used to fill deadair spaces, the process is similar to that for remedying cracks orleakages, but with a different layer arrangement. Studs are installed atstep 120. Exposed surfaces are coated with ISOBOND-E® at step 122.Install a first non-ceramic layer at step 124 and in one embodimentusing the non-ceramic layers to build a cone. Turbine mesh can be addedat step 126 to the first non-ceramic layer. A second non-ceramic layeris then applied over the turbine mesh in step 127. An expanded metallayer can be added at step 128 over the second non-ceramic layer. Thelayers are secured to the studs at step 130 and wire ties can be used tosecure the sealant layers around tubes at step 132. In step 134, theseal can be coated with ISOCOAT® which is available from HighTemperature Technologies, Inc.

Referring to FIG. 7, in an alternative arrangement for wall application,studs 136 are shown installed in a boiler environment. RTV 138 is shownapplied to the studs. First expanded metal layer is shown as 140, firstSil cloth layer is shown as 142 and first non-ceramic layer is shown as144. Turbine mesh is shown as 146. Second Sil cloth is shown as 148 andsecond expanded metal layer is shown as 150. The layers are attached toposts 152 using washers 153 which are carried by studs 136. Studs 136are secured to the wall for installation.

Referring to FIG. 8, studs 136 are shown having posts 152 is shown in acirculate configuration. This configuration can be used to not onlyremedy leaks and cracks, but also to fill “dead-air” spaces. Thematerial to be covered can be coated with ISOBOND-E® coating shown as154. A non-ceramic layer 144, turbine mesh 146, and a first expandedmetal layer 148 are coated with ISOCOAT® shown as 158. The layers areenclosed with wire 156 and bolted to posts 152 with washers 153.

It should be understood that this invention is applicable for bothremedying expansion joints and filling dead air spaces.

As used herein, an element or step recited in the singular and proceededwith the word “a” or “an” should be understood as not excluding pluralsaid elements or steps, unless such exclusion is explicitly recited.Furthermore, references to “one embodiment” of the present invention arenot intended to be interpreted as excluding the existence of additionalembodiments that also incorporate the recited features.

Exemplary embodiments are described above in detail. The assemblies andmethods are not limited to the specific embodiments described herein,but rather, components of each assembly and/or method may be utilizedindependently and separately from other components described herein.

While the invention has been described in terms of various specificembodiments, those skilled in the art will recognize that the inventioncan be practiced with modification within the spirit and scope of theclaims.

What is claimed is:
 1. A seal for use in high temperature environmentsof a boiler assembly to remedy cracks and air leaks, said sealcomprising: a high temperature silicone adhesive sealant layer; a firstnon-ceramic layer of high density fibers mounted to said siliconeadhesive sealant layer; a first expanded metal layer mounted to saidfirst non-ceramic layer; a first silicone cloth layer mounted to saidfirst expanded metal layer; a metal reinforcement layer mounted to saidfirst silicone cloth layer to provide structural integrity without theuse of ceramic materials; a second expanded metal layer mounted to saidmetal reinforcement layer; a second non-ceramic layer of high densityfibers mounted to said second expanded metal layer; a turbine mesh layermounted to said second non-ceramic layer; a second silicone cloth layermounted to said turbine mesh layer; a sealing castable applied over saidsecond silicone cloth layer to provide a covering; and a hightemperature bonding adhesive disposed between each layer following saidfirst non-ceramic layer to bind the layers together.